Biomedical subjects

H Y Zhou

Publications and source records attributed to H Y Zhou.

At least 19 recordsLinked to original sources

PubMed2005

Residue of pentachlorophenol in freshwater sediments and human breast milk collected from the Pearl River Delta, China.

Pentachlorophenol (PCP) was investigated in freshwater sediments and human breast milk collected from the Pearl River Delta, China. The average level of PCP in river sediments was 7.93 ng/g based on dry weight, ranging from 1.44 to 34.4 ng/g. As to the sediments from fishponds, samples from Zhongshan had the highest PCP levels (37.5 ng/g on average), followed by Dongguan (21.1 ng/g on average) and the least in Shenzhen (3.69 ng/g on average) and Shunde (2.20 ng/g on average). Negative relationship was obtained between the PCP level and pH value in sediment (r=0.553, n=13, p<0.05), while positive relationship was found between the PCP levels and the total organic matter (TOM) levels in sediment (r=0.700, n=17, p<0.01). These results indicated that pH and TOM played important roles during the process of PCP settling down to the sediment. PCP was also detected in human breast milk with an average of 2.15 ng/g. The PCP concentration increased with the age increasing of donors. The estimated PCP body burden for mother, daily and yearly PCP intake of infants ranged from 0.16 to 4.17 mg/person, from 0.26 to 10.23 mug/infant.day and from 0.09 to 3.73 mg/infant.year, respectively.

Adult↗

PubMed2005

Chitosan/cellulose acetate microspheres preparation and ranitidine release in vitro.

New microspheres containing hydrophilic core and hydrophobic coating as a controlled-release system with no toxic reagents were proposed. Water in oil in water (W/O/W) emulsion and solvent evaporation methods were used to make chitosan/ cellulose acetate (CCA) microspheres sized 200 - 400 microm. Ranitidine hydrochloride, as a model drug, was investigated for its release properties in vitro. The loading efficiency and release rate of ranitidine were affected by chitosan concentration and molecular weight. Higher loadings were obtained at lower concentrations in the interval of 1% to 2%. With chitosan at a 2% concentration microspheres could be obtained with more spherical appearance, smaller size, and higher ranitidine loading efficiency microspheres than at other concentrations. Among the different molecular weight chitosan (47, 145, 308, 499, and 1130 KD) microspheres, the high molecular weight chitosan (1130 KD) microspheres had relatively high loading efficiency (10%). Molecular weight and concentration of chitosan as well as the size of microspheres affected the release of ranitidine. Microspheres smaller than 280 microm released the drug faster than did the bigger by about 10%. The optimal condition for the preparation of the microspheres was chitosan concentration 2%, molecular weight 1130 KD. The ranitidine release from the microspheres was 30% during 48 h in phosphate-buffer saline medium.

Administration, Oral↗

PubMed2004

Screening of organochlorines in freshwater fish collected from the Pearl River Delta, People's Republic of China.

HCHs, DDTs, and PCBs were analyzed in fish flesh collected from fish ponds in the Pearl River Delta and compared with those from the Mai Po Marshes (a nature reserve) in Hong Kong, which was considered an unpolluted area. The concentrations for these contaminants were <0.01-7.8 ng/g lipid for HCHs, 22.3-381 ng/g lipid for DDTs, and 60-480 ng/g lipid for PCBs. Nevertheless, levels of HCHs and DDTs in fish flesh were lower than the China National Environmental Protection Agency maximum permissible limits set for foodstuffs. As for PCBs, 16% of fish collected from the Pearl River Delta exceeded the US EPA guideline concentration.

Animals↗

PubMed2001

[Diagnostic and therapeutic value of fiberbronchoscope for the adult in the children with respiratory diseases].

OBJECTIVE: To understand the diagnostic and therapeutic value of fiberbronchoscope for the adult in the children with respiratory diseases. METHODS: The results of diagnostic and therapeutic use in 107 child cases using fiberbronchoscope for adult were analysed. RESULTS: Pathogenic diagnosis was acquired in 107 cases; 17(17/21) cases of bronchial foreign bodies were extracted; 22 cases underwent bronchoalveolar lavage locally. CONCLUSION: Various type of BF of fiberbronchoscope for adult can be used in children at various ages, and to diagnose the child's diseases. Fiberbronchoscope for adult is safe and effective in the removing of foreign body and reliable in the treatment of atelectasis caused by inflammation, post-operation, and aspiration of foreign bodies. Fiberbronchoscope for adult can replace fiberbronchoscope for child unless the latter is used generally.

Adolescent↗

PubMed2001

[Relationship between sex hormone levels and blood calcitonin gene-related peptide/endothelin-1 in postmenopausal women with coronary heart disease].

OBJECTIVE: To investigate the relationship between sex hormone levels and blood calcitonin gene-related peptide/endothelin-1, and to evaluate the therapeutic effects of nylestriol. METHODS: Forty perimenopausal women without coronary heart disease (CHD) and 30 postmenopausal women with CHD were studied, and 30 postmenopausal women were divided into two groups and treated randomly with either 2 mg nylestriol or placebo. Serum 17 beta-estradiol (E2), testosterone (T), plasma calcitonin gene-related peptide (CGRP) and endothelin-1 (ET-1) were measured. RESULTS: In postmenopausal women, serum levels of E2 and plasma concentrations of CGRP decreased, while serum levels of T and plasma concentrations of ET-1 increased; E2 was positively related to CGRP, and negatively related to ET-1; T was negatively related to CGRP or ET-1. In the nylestriol group, compared with the parameters before treatment, plasma CGRP increased and ET-1 decreased after treatment. CONCLUSION: Estradiol possesses certain effects on endothelial cell, which may be an important aspect of its protective effects.

Calcitonin Gene-Related Peptide↗

PubMed2001

Effect of sea anemone toxin anthopleurin-Q on sodium current in guinea pig ventricular myocytes.

AIM: To investigate the effects of a sea anemone toxin anthopleurin-Q (AP-Q) isolated from Anthopleura xanthogrammica on sodium current (INa) in isolated guinea pig ventricular myocytes. METHODS: Single myocytes were dissociated by enzymatic dissociation method. INa was recorded using whole-cell patch-clamp technique. RESULTS: AP-Q (3 - 300 nmol/L) increased INa in a concentration-dependent manner. The EC50 value for increasing INa was 104 nmol/L (95 % confidence range: 78 - 130 nmol/L). AP-Q 300 nmol/L shifted the I-V curve to the leftward, changed the membrane potential of half maximal activation to more negative potential from (-36.3 +/- 2.3) mV to (-43 +/- 3) mV (n = 6, P < 0.01) and changed the membrane potential of half maximal inactivation to more positive potential from (-75 +/- 6) mV to (-59 +/- 5) mV (n = 6, P < 0.01). AP-Q 300 nmol/L shortened the half-recovery time of INa from (114 +/- 36) ms to (17 +/- 2) ms (n = 6, P < 0.01). The fast inactivation time constant (tauf) of INa was markedly increased by AP-Q 300 nmol/L. CONCLUSION: AP-Q has a stimulating effect on I(Na) with slowing the inactivation course of INa.

Animals↗

PubMed2000

[Effects of nitroglycerin and dexamethasone on nitric oxide and endothelin derived from alveolar macrophages in patients with mild and middle asthma].

OBJECTIVE: To investigate the changes about nitric oxide(NO), endothelin(ET) derived from alveolar macrophages(AMs) and the effects of nitroglycerin(NTG) and mexamethason(DXM) on ET and NO in patients with mild and middle asthma. METHODS: The AMs from 7 healthy control subjects and 15 patients with attacking asthma were purified, and divided into healthy control unpretreated(Group 1), asthmatic unpretreated (Group 2), asthmatic pretreated by DXM(Group 3), asthmatic pretreated by NTG(Group 4). All purified AMs were cultured for 48 hours. The NO level and ET level in supernatant and the expression of iNOS-mRNA, ET-mRNA of cultured AM from above subjects were examined by copper coated cadmiunm reduction, radioimmunoassay method and in situ hybridization respectively. RESULTS: 1. The AM of Group 1 secreted a little of NO, ET and expressed a little of iNOS-mRNA and ET-mRNA; 2. The NO and ET level in supernatant and the expression of iNOS-mRNA and ET-mRNAin Group 2 were evidently higher than those in other groups(P < 0.05, respectively); 3. The NO and ET level in supernatant and the expression of iNOS-mRNA and ET-mRNA in Group 3 were evidently decreased, but they were still higher than those in Group 1(P < 0.05, respectively); 4. The NO level in Group 4 was higher than that in other groups(P < 0.05, respectively); 5. The expression of iNOS-mRNA was negatively correlated with the NO level(r = -0.59, P < 0.05), and the expression of ET-mRNA was positively correlated with the ET level(r = 0.92, P < 0.01) in Group 4. CONCLUSION: The AMs from patients with asthma exacerbation secrete a large quantity of NO and ET because of the increasing expression of iNOS-mRNA, ET-mRNA; DXM can inhibit the expression of iNOS-mRNA and ET-mRNA, and decrease NO and ET level, but the NO and ET level are still abnormal; NTG can improve directly the production of NO and inhibit significantly the expression of iNOS-mRNA and ET-mRNA as well as decrease the ET level.

Adult↗

PubMed2000

[Study of the risk factors of blood pressure in children].

The blood pressure of 495 normal children aged nine to fourteen years were measured. The body height, weight, blood lipid profile, fasting blood glucosum(FBS) were also measured. The children's family history of hypertension and their dietary status and physical exercise status were investigated. The results showed that the older the child, the higher the blood pressure. On single factor analysis, systolic blood pressure (SBP) was positively correlated with age, family history of hypertension, intake of whole lipid milk, body height, weight, BMI, blood TC, LDL-C and FBS, whereas it was negatively correlated with the time of physical exercises and blood HDL-C/TC. Diastolic blood pressure(DBP) was positively correlated with age, body height, weight, IBM, FBS, blood TC and LDL-C, whereas it was negatively correlated with blood HDL-C/TC. Multifactor regression analysis showed that weight, age, blood TC and FBS had significant effects on SBP, while weight, age, blood TC and LDL-C had significant effect on DBP. Therefore, avoiding obesity, improving dietary status, taking more physical exercises and suitably lowering blood lipid and FBS should be carried out in children.

Adolescent↗

PubMed1999

Residues of organochlorines in sediments and tilapia collected from inland water systems of Hong Kong.

The levels and patterns of organochlorines including DDTs, HCHs, and PCBs were investigated in sediments and tilapia (Tilapia mossambica) collected from inland water systems [Tai Wai (S1), Fo Tan (S2), Siu Lek Yuen (S3), Tai Po (S4), and Tai Wo (S5)] in the New Territories of Hong Kong. Sediment and tilapia samples were also collected from two fish ponds for comparison. The ranges of DDTs, HCHs, and PCBs in river sediments were 2.82-8.63 ng/g (DW), 0.05-2.07 ng/g (DW), and 43-461 ng/g (DW), respectively. All these values were significantly higher (p < 0.05) than the pond sediments. Low chlorinated congeners (especially mono-, tri-, and tetrachlorobiphenyls) were enriched in sediment samples accounting for 70-80% of total PCBs. The ranges of DDTs, HCHs, and PCBs in tilapia muscle collected from Fo Tan and Tai Wai were 28.2-40.1 ng/g (DW), 2.04-3.76 ng/g (DW) and 267-310 ng/g (DW), respectively. These values were also significantly higher (p < 0.05) than those collected from the fish ponds. Higher chlorinated PCBs (tetra-, penta-, hexa-, and heptachlorobiphenyls) were commonly found in tilapia accounting for almost 60% of the total PCBs. The effect of lipid contents in organochlorines accumulation was not significant (p < 0.05) in general.

Animals↗

PubMed1998

Isolation of a novel bone glycosylated phosphoprotein with disulphide cross-links to osteonectin.

An 80 kDa protein was purified from calf bone by HCl-demineralization followed by 0.5 M EDTA/1.0 M NaCl extraction and sequential chromatography on DE-52, hydroxyapatite, and TSK-gel G3000SW HPLC columns. From the DE-52 column the protein was eluted at three different fractions, of which one further separated into two fractions on the hydroxyapatite column, indicating that the protein is present in four different molecular forms designated as 80 k-I-1, k-I-2, k-II, k-III. The N-terminal sequence analysis of all four forms gave the same sequence, SEQYNQEPNNV. Several tryptic internal peptides were also generated, purified and sequenced, leading to the identification of several repeat sequences, IFLGXXEI. Homology searching of the N-terminal and internal sequences indicates that this is a novel protein. Both 80 k-I-2 and k-III had similar amino acid composition with high contents of Asx, Glx and Leu and contained 7 and 16 phosphoserines per 1000 total amino acids, respectively. The 80 k-I-1 and 80 k-II forms were stained with Rhodamine B specific for phosphoproteins. The four forms contained different contents of neutral sugars ranging from 5.5 to 26% (w/w protein) and approximately 1.7% sialic acid. These data indicated that the 80 kDa protein exists in four isomeric forms, at least based on the different post-translational modifications. The evaluation of the 80 kDa glycosylated phosphoprotein under alkylating, reducing and non-reducing conditions indicated that this protein undergoes polymerization through intermolecular disulphide bonds. Furthermore, the 80 kDa protein and osteonectin (ON), both of which are cysteine-rich proteins, can cross-link with each other via disulphide bonds, and this process can be induced to take place in vitro under experimental conditions. The occurrence of such a phenomenon in vivo was confirmed from the presence of similar high Mr components containing both 80 kDa and ON in the same SDS/PAGE bands, detected by the respective antibody reactions in crude bone extracts which were extracted in the presence of alkylating agent.

Amino Acid Sequence↗

PubMed1998

Expression of bone microsomal casein kinase II, bone sialoprotein, and osteopontin during the repair of calvarial defects.

The temporal expression of bone microsomal casein kinase II, osteopontin, bone sialoprotein, alkaline phosphatase, and the accumulation of a solid calcium-inorganic orthophosphate mineral phase, have been charted from day 2 to day 21 during the repair of calvarial defects in rats induced by the implantation of decalcified rat bone matrix. Unlike the sequence of events that occur when the same decalcified bone matrix is implanted subcutaneously or intramuscularly, in which cases the first tissue to form in response to the implant is cartilage that subsequently calcifies and is later resorbed and replaced by bone, the repair of cranial defects is quite different. In the latter case, the first cells induced are undifferentiated mesenchymal cells and early fibroblasts followed by osteoblastic direct bone formation. Somewhat later a few small islands of cartilage are formed, widely separated and spatially distinct from the newly formed bone matrix. All of the cartilage and most of the implanted decalcified bone matrix are later resorbed and replaced by new bone by day 21. This in vivo model of the repair of a bone defect by direct bone formation has provided an excellent system to follow specific biochemical and physicochemical events. The total accumulation and rate of accumulation of the mineral and the two noncollagenous phosphoproteins (bone sialoprotein and osteopontin), as well as the activities of alkaline phosphatase, and for the first time either in vivo or in cell culture, the activity of microsomal casein kinase II, the major enzyme that phosphorylates the bone phosphoproteins, have been determined as a function of healing time in vivo. The overall general pattern of accumulation of the phosphoproteins and calcium-phosphate mineral phase and their relationships are similar to those reported in osteoblast cell cultures also monitored as a function of time.

Alkaline Phosphatase↗

PubMed1997

Assessment of trace metal distribution and contamination in surface soils of Hong Kong.

An intensive investigation was conducted to study the distribution of trace metals in surface soils of Hong Kong and to assess the soil environmental quality. From results of cluster analysis, and comparisons among soil types and areas, it is clearly shown that increases in trace metal concentrations in the soils were generally extensive and obvious in urban and orchard soils, less so in vegetable soils, whilst rural and forest soils were subjected to the least impact of anthropogenic sources of trace metals. However, some of the forest soils also contained elevated levels of As, Cu, and Pb. Urban soils in Hong Kong were heavily polluted by Pb from gasoline combustion. Agricultural soils, both orchard and vegetable soils, usually accumulated As, Cd, Cu, and Zn originating from applications of pesticides, animal manures, and fertilizers. In general, trace metal pollution in soils of the industrial areas and Pb pollution in the soils of the commercial and residential areas were obvious.

Journal Article↗

PubMed1996

Phosphorylation of purified bovine bone sialoprotein and osteopontin by protein kinases.

The large number of covalently bound phosphates on the extracellular phosphoproteins osteopontin (OPN) and bone sialoprotein (BSP) have been implicated in biological functions such as mineral deposition and osteoclast binding. In the present study the state of phosphorylation of BSP and OPN was evaluated by in vitro 32P labeling using a series of protein kinases and quantification. Both the purified bovine BSP and OPN were radiolabeled by [32P]ATP and factor-independent protein kinase. Quantification of 32P radioactivity incorporated on dephosphorylated BSP and OPN provided 6.6 and 8.9 mol of phosphate incorporated/mol, respectively. Native OPN incorporated 1.07 and BSP 2.46 mol of phosphate/mol by factor-independent protein kinase. These data led to calculations that OPN and BSP, respectively, contain 7.83 and 4.14 mol of phosphate/mol in their natural state. Thrombin digests of 32P-labeled BSP showed radioactivity to be associated with fragment of approximately molecular mass values 30 kDa (N-terminal half), with no observable radioactivity associated with the 40-kDa fragment (C-terminal half). Similar experiments with 32P-labeled OPN provided two radiolabeled thrombin fragments, with molecular mass 30 kDa (N-terminal half) and 20 kDa (C-terminal half), both were radioactive. The major phosphorylation was associated with the N-terminal half containing 7.0 mol of phosphate, and 1.9 mol of phosphate were associated with the C-terminal half. Additional experiments of in vitro phosphorylation of OPN and BSP by several other known protein kinases were carried out. cAMP-dependent protein kinase showed no phosphorylation of OPN or BSP, while protein kinase C and cGMP-dependent protein kinase led to minor phosphorylation, each of the latter introduced about 1 mol of phosphate/mol of OPN and BSP molecule.

Amino Acid Sequence↗

PubMed1996

Protein kinases of cultured chicken osteoblasts that phosphorylate extracellular bone proteins.

Cytosolic and microsomal protein kinase preparations from cultured chicken osteoblasts were found to phosphorylate up to six major proteins with Mrs 66, 58, 50, 36, 32, and 22 kDa in chicken bone extract. Use of heparin led to the conclusion that these proteins were predominantly phosphorylated by factor-independent protein kinase (FIPK) present both in microsomal and cytosolic preparations. It was confirmed that microsomal preparation contained predominantly FIPK, whereas cytosolic preparation contained additional kinases, that can phosphorylate the bone proteins. Use of purified chicken bone osteopontin (OPN) (58 kDa) and recombinant OPN led to the same conclusions. The identify of the protein kinases was clearly established by using a series of synthetic peptide substrates. Quantitative analysis utilizing pure protein kinases and purified chicken bone OPN, recombinant mouse OPN, and bovine bone OPN and BSP led to introduction of approximately 9 moles of phosphate/mole of OPN and 6.6 moles phosphate/mole bovine bone sialoprotein (BSP) by casein kinase II. cGMP-dependent protein kinase and protein kinase C both introduced 0.5-1.2 moles phosphate/mole of OPN and BSP, whereas cAMP-dependent protein kinase led to no significant phosphorylation of OPN or BSP. Consistent with the above results, sites of phosphorylation identified for OPN (metabolically labeled) and BSP (labeled by casein kinase II) revealed that predominant phosphorylated sites have recognition sequences for FIPK.

Amino Acid Sequence↗

PubMed1996

[Effects of L-malate, an inhibitor of glutamate decarboxylase, on learning and memory in mice].

Oral administration of L-malate 600 mg.kg-1 for 5 days before training can significantly promote memory acquisition, consolidation and retrieval, respectively, on anisodine-, chloramphenicol-, and ethanol-induced memory impairment in mice. Ketamine (8.5 mg.kg-1, i.p.), a selective NMDA receptor antagonist, was found to inhibit the anti-amnesic activity of L-malate. The glutamate (Glu) and GABA content in mice brain was measured by high-performance liquid chromatography with fluorescence detection. The content of GABA was shown to be decreased from 2.3 +/- 0.5 mumol.g-1 to 1.3 +/- 0.5 mumol.g-1 (P < 0.01), so the Glu/GABA ratio was increased significantly. These results suggest that the decrease of cerebral GABA level and the increase of Glu/GABA ratio is favorable to learning and memory.

Animals↗

PubMed1995

Stimulation by bone sialoprotein of calcification in osteoblast-like MC3T3-E1 cells.

Bone sialoprotein (BSP) containing an Arg-Gly-Asp cell-binding sequence was purified from bovine bone 4 M guanidine-HCl extract after HCl demineralization by a series of chromatographic procedures. When this protein was coated on culture dishes in the presence of type I collagen, it increased both DNA content and alkaline phosphatase (ALP) activity in osteoblast-like MC3T3-E1 cells, and stimulated calcification in the cells, whereas fibronectin, another cell-binding protein, showed a marked increase in the DNA content but had little effect on the ALP activity. These findings suggest that BSP is mitogenic for preosteoblasts and differentiating the cells into osteoblasts, thereby stimulating bone calcification.

3T3 Cells↗

PubMed1993

Differences in composition of cell-attachment sialoproteins between dentin and bone.

Matrices of dentin and bone were compared with respect to the content of cell-attachment sialoproteins. The levels of two sialoproteins, osteopontin (OPN) and bone sialoprotein (BSP), were determined in dentin and bone by immunochemical procedures. Polyclonal antibodies against bovine BSP and an antibody against the amino-terminal decapeptide of rat OPN were used. The relative levels of OPN and BSP in dentin were less than one-tenth of the levels in bone. The differences between dentin and bone levels of OPN and BSP were thus larger than those for osteonectin or bone Gla protein in the two tissues. The scarcity of the cell-attachment proteins in dentin may reflect the metabolic inactivity of dentin.

Animals↗

PubMed1993

Reactivity and sensitivity of the mesenteric artery in adult spontaneously hypertensive rats after chronic treatment with indapamide.

The effects of chronic treatment with indapamide (3 mg/kg/day) on the structure and function of the mesenteric artery were studied in two groups of spontaneously hypertensive rats (SHRs) using an experimental model of in situ localized mesenteric artery. Indapamide (n = 12) or placebo (n = 12) were given to 8-week-old rats for 4 weeks. After anesthesia and laparotomy, a segment of mesenteric artery (external diameter, 300-400 microns) was exposed for video-microscopic measurements. The diameter-pressure relationships were established under active conditions (phenylephrine, 10(-6) M) and passive conditions (potassium cyanide, KCN) for transmural pressure ranging from atmospheric pressure to 200 mm Hg. These studied arterial segments were then fixed and their wall cross-sectional areas (CSA) measured in transverse sections. Active wall stress and tension were defined as the differences in wall stresses and wall tensions calculated for active and passive conditions. Systolic arterial pressure and mesenteric CSA were decreased in treated rats (197 +/- 15 mm Hg vs. 211 +/- 12 mm Hg, p < 0.05; 16,230 +/- 1048 microns2 vs. 19,033 +/- 1082 microns2, p < 0.05). In both groups, mesenteric diameters were smaller under active than under passive conditions without significant differences in treated vs. untreated group under active conditions. The active wall tension was lower in treated (0.4 +/- 0.19 N/m) than in untreated rats (1.19 +/- 0.62 N/m, p < 0.05). However, there were no differences in active wall stress in both groups (103 +/- 47 kPa and 134 +/- 30 kPa).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗